FIGURE SUMMARY
Title

Comparative sequence analysis and functional validation identified a retina-specific enhancer around zic5 and zic2a

Authors
Zhang, Q., Li, T., Zhang, Y., Lin, J., Chen, X., Gui, Y., Li, Q.
Source
Full text @ Gene Expr. Patterns

Identification of an eye-specific enhancer. (A) Sketch map of the position distribution of 5 ECR near zic5 and zic2a. Genes are shown as thick arrows, and their orientation indicates the translational direction of genes. ECRs are indicated by red rectangles. (B) ECR3 sequence alignment between human (hg19 assembly) and zebrafish (danRer7 assembly). (C) Lateral view of ECR3 driven GFP expression specifically in zebrafish eyes at 24hpf, 48hpf and 72hpf. Scale bar = 200 μm in all panels.

Whole 290bp sequence of ECR3 is essential for eye-specific enhance feature. (A) Sequence sketch map of ECR3, ECR3-1and ECR3-2. Highly conserved 170bp ECR fragment of 170bp is located in the second half of ECR3, and ECR3-1 contains its entire sequence. ECR3-2 contains the first half of ECR3 and part of 170bp highly homologous region. (B) Lateral view shows that ECR3, ECR3-1, ECR3-2 drives GFP expression at 36hpf. Scale bars = 400 μm in all panels.

Tg (ECR3-290: GFP) exhibits green fluorescence specifically in GCL. (A–D) Confocal images show Lateral view of GFP expression in retina at 24hpf, 48hpf, 72hpf and 7dpf. Fluorescence intensity and expression area was at highest at 24hpf, then the expression region diminished at 48hpf until it confines to the cells circled around outside of the lens at 72hpf. Scale bar = 100 μm (E-E′) Frozen section shows GFP expressed in GCL at 4mpf zebrafish retina. Scale bar = 1 mm. E′ shows magnification of white box in E.

zic2a and zic5 expression pattern at 24hpf and 48hpf. In situ hybridization of zic2a (A, A′, C, C′) and zic5(B, B′, D, D′) in the wide type embryos at 24hpf (A-B′, arrows indicate expression signal) and 48hpf (C-D′, arrows indicate expression signal). Dorsal is upwards; anterior is leftwards. Scale bar = 150 μm in A′, B′, C′, D'.

Acknowledgments
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Reprinted from Gene expression patterns : GEP, 39, Zhang, Q., Li, T., Zhang, Y., Lin, J., Chen, X., Gui, Y., Li, Q., Comparative sequence analysis and functional validation identified a retina-specific enhancer around zic5 and zic2a, 119162, Copyright (2020) with permission from Elsevier. Full text @ Gene Expr. Patterns